Besides the basic defrag what else can I do to optimize my computer to run better?

Q: I have a Compaq Presario 2200 laptop computer. Recently, it has been running slowing (e.g. taking a lot of time to open simple programs). I defragmented the disk a few weeks ago, but it is still running slowly. I don’t have that much on the laptop – the usual programs – Office 2003, Windows Media Player, iTunes, Nikon Picture Project (I have about 300 pics stored)

Is there anything else I can do in the way of regular maintenance to improve performance?